1. Field of the Invention
Primary Concept
The present invention relates generally to methods and apparatus for humidifying a compartment, and, more particularly, to humidifying the crew and passenger compartments of a large commercial aircraft.
2. Discussion of Background and Prior Art
a. Prior Aircraft Humidification Systems
A primary problem faced by crew members of large commercial aircraft is that the air distributed to the crew compartments is very dry and causes respiratory and visual problems on long flights. Aircraft, such as, the Boeing 747, the AirBus 300, the McDonnell Douglas DC10 and the soon to be introduced new long range airliner the Boeing 777, can stay aloft for long periods of time. The dry air distributed to the cockpit causes dryness of the skin and mucous forming membranes of the body resulting in physical discomfort, including contact lens irritation and nasal and sinus respiratory problems. Similar problems are experienced by passengers in the passenger compartments of the aircraft.
Humidifiers for aircraft to solve the dry air problem are known, but are not commercially successful. The major airlines have either completely stopped using prior humidifier systems or endure the numerous problems that afflict these prior systems. These problems center around residual particles left behind after the water evaporates or mechanical and health hazards created by distributed water droplets. These problems are set forth generally below:
(1) Contaminant build-up in the humidifier. Prior humidifiers require frequent maintenance because water minerals build-up on the humidifier parts.
(2) Maintenance Required Before "C" Check. The aforesaid build-up forces maintenance every several hundred hours of operation, which is sooner than airlines preferred maintenance at "C" check intervals only.
(3) Contaminant Build-up In The Ducts. Prior humidifiers spray water mist into the distribution system causing contaminant build-up on duct walls which can eventually restrict air flow or cause duct replacement.
(4) Dust In Personnel Compartment. Prior water mist spray humidifiers cause water soluble residual minerals left after the water evaporates from the mist droplet to blow through the personnel compartment as "dust".
(5) Growth of Pathogens. Water sumps support the growth of bacteria and fungus. In prior humidifiers with water sumps, these pathogens become entrained in distributed air, are inhaled by the flight crew and can cause crew member illness.
(6) Water In Air Distribution Duct. Unevaporated water in the form of water droplets entrained in distributed air of prior systems falls out and causes "rain" in the aircraft air distribution system and the served crew compartments, for example, as water dripping out of flight deck outlets causing serious flight hazards.
The present invention overcomes these problems through utilizing the principle of efficiently blowing air through a body of water in a chamber. The air cools as water evaporates into the air. Excess water droplets are separated out, the humid air is filtered and is then mixed with air supplied to the compartment. No such humidification system is known for use in aircraft prior to the present invention.
b. Other Prior Humidification Systems
Bubbling hot air through a body of water and inhaling the discharged humid air is known for use in treating respiratory ailments in the medical field. Such small portable systems may include a partial wall as a baffle plate in the path between the body of water and the outlet to prevent bubble turbulent water from directly entering the outlet port. U.S. Pat. Nos. 4,098,853; 3,864,440; 4,100,235. These systems do not filter the air and are unsuitable for use in humidifying aircraft compartments for the reasons stated above.
A gas washing system is known which passes dirty air centrally, downwardly into a body of water and then turns the air outwardly through a venturi while mixing spraying water with the air to strip entrained particles from the air which then bubbles to the surface of the body of water and passes through a drying apparatus to remove entrained water droplets before exiting the washer apparatus. U.S. Pat. No. 3,756,580. This method is not a humidification system, preferring dry outlet air instead, and it does not optimize the atomization and saturation of the air with water. Unlike the present invention, this system is unsuitable for use in an aircraft humidification system.
A known vehicle air temperature control system uses an ultrasonic vibrator as a humidifier to blow humid air through a duct directed at the driver's face. U.S. Pat. No. 4,340,112. Such a system fails to recognize the advantages of blowing a dry air source through the body of water to evaporate water droplets and mechanically removing the excess droplets and filtering the humid air before discharging it.
A prior greenhouse or agricultural use humidification system is known which bubbles air upwardly from below a body of water and has a number of sensors enabling automatic control of humidity, air temperature and water temperature. This system fails to recognize the increases in operating efficiencies and control achievable by baffling, and filtering the humid air to eliminate excess droplets and entrained minerals, and by properly atomizing the air in the bubbling process.
The latter two prior systems also suffer from many of the problems mentioned above which prevent their practical use in an aircraft humidifier system.
Of critical importance is the factor of the safety of the crew and passengers of the aircraft. Any aircraft system must be controllable from the cockpit while in flight, virtually fail safe and extremely reliable and durable. This high, exacting standard is necessary due to the narrow margin for error and the extreme danger to the lives of crew and passengers when handling emergencies while airborne. Extended required maintenance intervals allowing system inspection during routine programmed maintenance periods is also highly desirable for reducing failure risks and increasing operating efficiencies.
There is a long felt, present need for a humidification system for an aircraft that optimally saturates the air with water, retains dissolved minerals in uniform concentrations in the body of water, is periodically drainable at extended intervals, prevents distribution of excess water droplets, pathogens and residual minerals to the personnel compartments, uses no moving parts other than in the control elements, and is automatically controllable from the flight deck of the aircraft while meeting the exacting safety standard required of aircraft systems.
It is the object of the present invention to fill this long felt need.